To make matters more interesting, the Vermont Center for Geographic Information (VCGI) publishes a lot of Vermont-related GIS data, including the shapefile containing all the road centerline data that AOT uses to create the Town Highway Maps.

What does this mean? Two things, primarily:

It's not terribly difficult to create a Garmin-formatted vector map that clearly shows all of the less-than-class-three roads. This is helpful if you're looking for fun places to play; it's also helpful to glance at a GPS and realize that no, you probably don't want to take your K bike up that road (then again, you might). It's also possible to include the private roads and discontinued roads from the AOT data, which helps clarify the status of some roads so you can more readily identify class-four roads and legal trails versus private roads (and/or know when to be very polite and apologetic if caught, if your'e one of those types). To save you the trouble, I've created such a map file; you can download the Garmin map file here (drop that in the \GARMIN folder on either your mini-SD card or directly on your device); you can also grab the GMAP-formatted map if you want to install it into Basecamp.

Two caveats: this is not a routable map. Creating a routable map is significantly trickier, while creating a vector overlay like this is relatively easy (see below for full details). Also, the data is what it is—there are definitely errors. If someone claims that you're on their private property despite the GPS file indicating a public right-of-way, they may actually be right, and the AOT data may be wrong.

If you're willing to geek out on the mapping stuff a bit, you can use QGIS to do some of your route planning. You could use ArcGIS, too, if you happen to have that handy, but then you probably know more about this stuff than I do. Why QGIS? It's free, there is reasonable documentation for it...and you can import all sorts of data layers to help in your planning. If you want to get started and figure out the details later, get QGIS installed, create a new project, set the project CRS to WGS84 (EPSG 3857), then grab the TransRoad_RDS layer from VCGI and add it as a vector layer. You'll now have a bunch of monocolor lines for all Vermont roads, which isn't really all that helpful. Grab this exported style and apply it to the Trans_Roads_RDS layer; you should get a relatively reasonable map, with paved and gravel roadways identified in grey (double lines for paved, single for gravel), class four gravel roads in solid, forest green, and various qualities of class four roads in various pink dots and dashes (the more gaps in the line, the lower the quality of roadway according to the AOT data). Install the OpenLayers plugin from the Plugins -> Manage plugins menu, then go back to the plugins layer and add a Google Satellite layer. Make sure the roads are drawn on top of the satellite layer, and you should be able to do a bit more research about what might go.

For a visual of what the map looks like in QGIS with my style file applied, check out these (large) PDFs:

So the act of creating the Garmin IMG file (i.e. the file that goes on the GPS) and the GMAP file (that you can install into Basecamp), as I've done it, requires a few steps:

Create GPX files holding the map data
Export each class of road as one GPX file full of routes (e.g. All class four gravel roads as one GPX, all class four "Graded and Drained" as another, all class four "Unimproved or Primitive" as another, all class four "Impassable or Untravelled" as another...etc).

You can do this with QGIS by querying the TransRoad_RDS layer; queries use SQL syntax and the metadata is described in the text file that came with the data layer. For example, class 4, graded and drained, would be RPCCLASS = 4 AND SURFACE = 3. Start by making sure you can see the entire layer (Using the "Zoom to layer extent" option is a good way to do this). Select the layer in the layers panel, right-click and choose 'Query", then enter the appropriate query. Only those elements in the layer that match that query will remain displayed. You can then use one of the selection tools to select all of the roads.

Once you have a set of items selected, you can right-click the layer and choose "Save selected as…", then select:
Format: GPS eXchange Format [GPX]
Encoding: Selected CRS
CRS: hit "Browse" and find EPSG 4326 (WGS 84)
Check "Skip attribute creation"
Then choose the filename for the GPX file and hit "OK"

Repeat these steps for each class of feature that you want in your Garmin maps. If you want to skip this step and just want to play with the formatting of the map in the next step, I did ZIP and upload the GPX files I used:

Now that you have the GPX files you want, you'll need IMGfromGPX. Fire it up and drop the GPX files you created onto the app's window. The first few columns should populate with the name of the file, the number of POI points, and the number of tracks contained in the file.

In the last column, you can then assign a color to each type of line.

Now, here's where it gets a little tricky: the default TYP files provided with IMGfromGPX only support eight types of line, and they all look the same except for coloration. Not only is that boring, it's tough to use on the road, especially in conjunction with another map. To rectify this, we'll use a modified TYP file by using the online Garmin TYP editor, at least if it's still working—the site author has suggested that he plans to shut it down in the near future.

You can either start from scratch or from an existing TYP file. It's easiest to start from an existing file; you can use one of the files that come with IMGfromGPX or you can grab the TYP file I created. Edit the eight line types in the file to your liking, keeping track of which you want to use for which GPX file.

The correlations are:

Black highway,motorway Line type 0x01

Red highway,trunk Line type 0x02

Green highway,primary Line type 0x03

Yellow highway,secondary Line type 0x04

Blue highway,tertiary Line type 0x05

Magenta highway,unclassified 0x06

Cyan highway,service Line type 0x07

Grey highway,cycleway Line type 0x16

White area landuse,military Type 0x04

Red area landuse,retail Type 0x08

Green area landuse,industrial Type 0x0c

Yellow area landuse,meadow Type 0x17

Blue area landuse,recreation_ground Type 0x19

Magenta area landuse,reservoir Type 0x3f

Cyan area landuse,farm Type 0x4e

Grey area landuse,forest Type 0x50

In other words, whatever styling is defined in the TYP file for a "highway,motorway" — type 0x01 or "Major HWY thick" in the editor — will be displayed on lines set to "Black" in IMGfromGPX.

Once all the styling is as you wish (or as you think you wish, I had to go back a couple of times, as it turns out that a single-pixel-wide line doesn't show up very well), you will need to get the TYP file in the correct location (this varies depending on your OS, but it is explained in the IMGfromGPX help file) and then select the TYP file in the drop-down. If you add the TYP file after starting IMGfromGPX, you will need to restart the app to make it show up in the list.

You should choose a Map ID other than the default; I've been using 4,000-series numbers, as Garmin products generally seem to be under 1,000 and OSM uses 2,000. You can only have one map with a given family code installed on a device, so if you want to have more than one map available—e.g. if you create one IMG file for Vermont and then another for New Hampshire—you will need to give each map its own family ID.

Fill in the "Name on computer" and "Name on device"; I usually use the same value in both fields so I don't confuse myself. Keep in mind that the display may be shortened on the device and it helps if you can still recognize the map name. You can choose to either create the IMG file right away or create the GMAP file, install that, and then use the Garmin tools to install the IMG file on the device; I recommend creating the IMG file right away and then just dropping it in the \GARMIN folder on your device—assuming you're dealing with a similar size data set, the file is small and skipping the map-creation step with the Garmin tools saves a bit of time.

So, speaking of that IMG file, make sure it's named something useful (not the default gmapsupp.img) and copy it to your \GARMIN directory, either on a memory card that you will install in the GPS or on the device itself. When you next power up the device, you should have your new map available—congratulations!

Now, go look at an area or two with which you are familiar and make sure that things appears as you expected. My initial go-round had discontinued roads and open class four roads appearing the same, which is obviously not the desired behavior.

Coming up next (though not tonight): planning a ride with QGIS and using various data in that process.

thanks for sharing all this will try some out this weekend...
is it possible to create more than one map with imgfromgpx and have it display in mapsource and be loaded on the older (60csx) gps. I created a map from class 3 roads, loaded into mapsource then onto gps. Then created a map from puppydog trail gpx file and loaded into mapsource but the class 3 road map was gone so I could not load both onto the gps.

thanks for sharing all this will try some out this weekend...
is it possible to create more than one map with imgfromgpx and have it display in mapsource and be loaded on the older (60csx) gps. I created a map from class 3 roads, loaded into mapsource then onto gps. Then created a map from puppydog trail gpx file and loaded into mapsource but the class 3 road map was gone so I could not load both onto the gps.

On the newer GPSes, you can have multiple maps active (e.g. I usually have the Vermont roads map I created loaded as well as the OSM routable maps). You do need to change the map family ID on each map. I don't know about the 60csx.

I did use a different number in the lower left box but didn't help. I did create a map using img2gpx using the puppydog gpx file and it did not make the imgfromgpx map go away I can get at least 2 custom maps into mapsource and am now load onto gps...

It appears that you can only have one IMG file on the 60CSX. You can use the Garmin tools to load multiple mapsets into one IMG file on the device and then select between them from the Maps page (Menu, Setup Map, right rocker until you get to the i-in-a-circle, select it, then hit Menu again to select or deselect maps, according to http://asiteaboutnothing.net/g_60csx.html).

Does that answer your question? I'm not quite sure what the limitations of the 60csx are, so I'm not sure if I can be much more help or not.

got it figured out...evidently I used the same map id # twice.
getting multiple maps onto the 60 is no problem as long as they are in mapsource. but yes there is only one map file allowed on the 60 but the file can contain many maps

So, speaking of that IMG file, make sure it's named something useful (not the default gmapsupp.img) and copy it to your \GARMIN directory, either on a memory card that you will install in the GPS or on the device itself. When you next power up the device, you should have your new map available—congratulations!

So a slight update on this: some GPS devices require that the supplementary map file be named gmapsupp.img. Others—such as the Montana, Monterra and Oregon—do not. If the file doesn't work with a human-helpful name, try using gmapsupp.img (as long as you don't already have another file by that name in the \GARMIN folder).

Also of note, the AOT has released 2014 data. I'm working on updating the Garmin files, but here are the large PDFs:

this is great! i was able to get the new gmapsupp.img installed to my Oregon and can see the new map data (simple drag/drop after renaming the file). i'm having trouble though installing the .gmap file to base camp. after i download the .zip file, it unzips as a regular folder; unsure as to what to double-click to install. running mac os 10.9 & base camp 4.3.

this is great! i was able to get the new gmapsupp.img installed to my Oregon and can see the new map data (simple drag/drop after renaming the file). i'm having trouble though installing the .gmap file to base camp. after i download the .zip file, it unzips as a regular folder; unsure as to what to double-click to install. running mac os 10.9 & base camp 4.3.

It should be a bundle file, which is a folder with a special setting so that the Mac treats it as one file (e.g. an .app bundle opens the app when you double-click it, but it's actually a folder with other files and folders within).

Try VtRoads14.dmg, which is a disk image file; when you open that, you should find within the .gmap bundle, which in turn should be double-clickable.

VTRoads doesn't overlay the Global Base map however, i.e. it's one map or the other. is this the intended set up, or is the method above missing it?

regardless, thanks for the work on this!

Glad you got it working. And yes, that is an unfortunate limitation of BaseCamp—although Garmin makes plenty of GPS devices that can overlay maps, BaseCamp does not support that (much to my chagrin—I'd love to have the class 4/legal trail data overlaid on my normal OSM basemap for route planning, to make sure that those fun sections only sneak in when I intend for them to do so).

GPX files (note that these will probably make Garmin devices and programs very unhappy due to the volume of track objects per file):Here

The earlier GPX files you posted were zip files that when unpacked, imported into Mapsource and Basecamp.

The GPX files referenced above will not open directly in Mapsource or Basecamp on my PC, I get a "could not be imported" error message. Is it possible that they are zip files? Or is my program just "unhappy" with the GPX file and refusing to open it?

Helpful points:
a) it includes the ESITES layer, which maps items (structures, hydrants, public phones, etc) that are likely to be of interest for E911 dispatch purposes. If there are a bunch of camps out in the middle of the woods near a class-four road or legal trail, that class-four road or legal trail is likely to be passable, at least with the right vehicle and skill set.
b) it includes VAST trails. Although VAST trails on public and private land are almost all closed to wheeled travel, some of them travel class-four and legal-trail right-of-ways which are open to wheeled travel. Surface conditions may vary, but trails are unlikely to be particularly overgrown.
c) The black-and-white imagery (click "ESRI Imagery" and choose "Vermont black-and-white") is great for getting a better look at an area when compared to Google satellite

Not-so-helpful:
a) Although legal trails and class-4 roads are included, in many cases the other uses of a way seem to trump for rendering purposes (e.g. near here, I saw a couple of places where class-four roads were marked as driveways, contrary to reality). Cross-reference the other materials above for best results.